1. Field of the Invention
The present invention relates to a full color organic light emitting diode (OLED) and a method of fabricating the same.
2. Description of the Related Art
Generally, an organic light emitting diode (OLED) display device is a display device which emits light when electrons and holes injected into an emission layer from an electron injection electrode, i.e., a cathode, and a hole injection electrode, i.e., an anode, are recombined with each other to create excitons that transition from an excited state to a ground state.
Thus, unlike a conventional liquid crystal display device, the OLED display device does not need a separate light source, and thus can be decreased in volume and weight.
The OLED display devices may be classified into a passive matrix type and an active matrix type according to a driving method.
The passive matrix OLED display device has a relatively simple structure fabricated by a relatively simple method, but requires higher power consumption and is difficult to form into a large-sized display. Also, in the passive matrix OLED display device, an aperture ratio decreases as the number of interconnections increases.
Accordingly, for small-sized display devices, passive matrix OLED display devices are frequently used, whereas for large-sized display devices, active matrix OLED display devices are frequently used.
Further, OLED display devices may be classified into bottom-emission types and top-emission types according to the direction of light generated from an emission layer. The bottom-emission type display emits light toward a substrate utilizing a reflective electrode or a reflective layer as an upper electrode, and a transparent electrode as a lower electrode. Here, in the active matrix OLED display device having a thin film transistor, because light generally cannot penetrate the thin film transistor part, the aperture ratio, or the area through which light passes, may be reduced. On the other hand, the top-emission type display emits light away from the substrate, utilizing a transparent electrode as an upper electrode and a reflective electrode or a reflective layer as a lower electrode. Thus, the aperture ratio, or the area through which light passes, is increased, and brightness can be improved.
Meanwhile, in a full color OLED display device including blue, red and green pixel regions, the red pixel region has a relatively shorter afterimage life span than the green and blue pixel regions, and thus full color reproduction by the device may be degraded.